For example, touch screens are classified into three types: add-on type touch screen, on-cell type touch screen, and in-cell type touch screen. In the on-cell type touch screen, a touch electrode is provided between an opposed substrate of a display panel and a polarizer provided on a side of the opposed substrate. The on-cell type touch screen has high yield and will not reduce an area of a display region of the display panel.
In a current on-cell type touch screen, transparent conductive oxide materials (such as, Indium Tin Oxide (ITO)) are used to fabricate the touch electrode on a glass substrate which is provided on a light emission side of the touch screen. Since a difference between a refractive index of the ITO and a refractive index of the glass substrate is relatively large, in a state where the touch screen is not turned on, there are relatively large optical path difference and phase difference between reflected light of external natural light in a region having the touch electrode and reflected light of external natural light in a region not having the touch electrode, resulting in a problem of poor shadow elimination in the touch screen. In addition, since a difference between a transmittance of the ITO and a transmittance of the glass substrate is relatively large, in a state where the touch screen is turned on, the transmittance of light inside the touch screen in a region having the touch electrode and the transmittance of light inside the touch screen in a region not having the touch electrode are different, resulting in white stripes in the touch screen.
In order to solve the above problems, a shadow elimination glass is used as the glass substrate which is provided on the light emission side of the touch screen; or, a transparent inorganic insulation thin film having a refractive index similar to that of the ITO is deposited on the touch electrode. The shadow elimination glass has high cost; in the case that the shadow elimination glass is used as the glass substrate of the touch screen, the fabrication cost of the touch screen is increased. In addition, the inorganic insulation thin film is deposited at relatively high temperature (for example, above 200° C.); in the case that the inorganic insulation thin film is deposited on the touch electrode, damages to the touch screen easily occur.